Answer: 4H → He-4 + energy.
- A 4H → He-4 + energy
- B 4H → He-3 + energy
- C 2H → H-2 + energy
- D H → n + e
Correct answer: A. 4H → He-4 + energy
Explanation: PP chain net result: 4 ¹H → ⁴He + 2 e⁺ + 2 neutrinos + 2 gamma + 26.7 MeV energy. Powers the Sun.
Binding energy per nucleon rises sharply for light nuclei, peaks around iron-56 (the most stable nucleus), then slowly declines for heavier nuclei - which is exactly why fusing light nuclei or splitting heavy nuclei both release energy: each moves the products toward this stability peak.
Concept context
Radioactivity, nuclear reactions, fission, fusion, and binding energy.